These elements, with atomic numbers of 113, 115, 117, and 118 comprise the missing parts of period 7 – the lowest row – of the periodic table.

Discover the history, structure, and importance of the periodic table of elements, from Mendeleev’s discovery to modern scientific applications.

The heaviest recognized chemical element with the atomic number 112 was discovered at the GSI Helmholtzzentrum für Schwerionenforschung and -- since February 19, 2010, -- officially carries the ...

Atomic Number: 69 Atomic Symbol: Tm Atomic Weight: 168.93421 Melting Point: 2,813 F (1,545 C) Boiling Point: 3,542 F (1,950 C) Word origin: Thulium is named for Thule, the earliest name for ...